The invention relates generally to combustion dynamics and, more particularly, to combustion dynamics in gas turbine combustors.
Fuel injection and mixing are critical to achieving efficient and clean combustion in gas turbine engines. Fuels can be provided in two forms, namely gaseous form and liquid form. In the case of gaseous fuels, it is desirable to obtain an optimal level of mixing between air, fuel, and combustion products in a combustion zone. When liquid fuels are employed, they are atomized into small droplets and distributed in an air stream before entering the combustion zone.
Exhaust gases from gas turbine engines contain substances such as Nitrogen Oxides (NOx) that are harmful regulated emissions. Hence, there has been increased demand in recent years for gas turbines that operate in partially premixed (PP) or lean, premixed (LP) mode of combustion in an effort to meet increasingly stringent emissions goals. Partially premixed (PP) and lean premixed combustion reduces harmful emission of Nitrogen Oxides without loss of combustion efficiency.
However, combustion instabilities, also known as combustion dynamics, are commonly encountered in development of low emissions gas turbine engines. Combustion dynamics in the form of fluctuations in pressure, heat-release rate, and other perturbations in flow may lead to problems such as structural vibration, excessive heat transfer to a chamber, and consequently lead to failure of the system.
Therefore, a need exists for an improved system for controlling combustion dynamics that may address one or more of the problems set forth above.